Galvanic cell.



UNITED STATES. PATENT OFFICE.

' MORDUCH L. KAPLAN, OF BROOKLYN, NEW Y ORKJ No Drawing.

To all whom it may concern:

Be it known that I, MORDUGH L. KAPLAN, a citizen of the United States,and a resident of Brooklyn, in the county of Kings and State ofNew York,haveinventedcertain new and useful Improvements in Galvanic Cells, ofwhich the following is a specification.

This invention relates to. galvanic cells (of the Leclanch type)consisting of a negative zinc pole, a positive carbon pole, anelectrolyte containing ammonium chlorid or other ammonium salts, and thelike and adepolarizing mass comprising powdered graphite or other formof conducting carbon, incorporated with an oXid of manganese of novelcharacter and high efliciency as a depolarizing agent and relates inparticular to dry cells or batteries, especially the form known as theminiature dry cell; and as more particularly hereinafter described indetail and set forth in the appended claims.

The present form of galvanic cells of the Leclanch type, as is Wellknown, consists of a negative zinc pole, a positive carbon pole, anelectrolyte containing ammonium chlorid or other ammonia salt, and adepolarizing mass consisting of a mere mixture of powdered graphite orother form of carbon, with a higher oxid of manganese, such as manganeseperoxid, MnO Pulverized natural manganese peroxid, as for example, themineral pyrolusite, commonly haSbeen-used for this purpose, although anartificial form of the hydrated peroxid, obtained by its precipitationby reagents from solutions of manganese compounds, also has beenemployed to some extent. It is diflicult to grind the natural mineralmanganese material to as fine a degree as is desired,

and the precipitated manganese material, although finely-divided, iscommonly very bulky; due no doubt in part at least to its Water ofhydration, so that depolarizing material in sufiicient quantity canscarcely be crowded into the small space available for the depolarizingelement. Furthermore the hydrate water lowers the percentage of activeoxygen.

Manganese peroxid, substantially 0r essentially free of hydrate waterand of a very desirable high specific gravity, can be obtained byheating manganese nitrate to about 160 C. Although rich in activeoxygen, the baking operation produces Specification of Letters Patent.

during the heating operation.

GALVANIC CELL.

Patented Nov. 16, 1915.

Application filed December 24, 1914. Serial No. 878,918.

lumps which are diflicult to pulverize or to put into condition toaiford any real or intimate contact of the depolarizing and conductingmaterial.

Attempts have been made to secure a more intimate contact of thedepolarizing material and the conducting body, and to improve therelatively low efficiency of the cell in the case of a depolarizing massconsisting of a mere mixture of powdered graphite or other form ofcarbon with pre-formed or ordinary manganese peroxid. It has even beenproposed to impregnate a porous carbon electrode with a solution of amanganese compound, such as manganese nitrate, and to then beat to asufficient temperature to decompose this material and drive off theacid,- thus leaving the carbon rod or structure more or less coated withmanganese peroxid wherever the solution comes in contact with the carbonsurface lVhile in some measure an increase in the efliciency is possiblyderived by such treatment, it is difficult to secure a suflicient amountof deposited manganese peroxid in contact with the conducting materialunder such conditions as to obtain uniform depolarization andconductivity, while using such quantity of the peroxid asto afford thedesired life to the cell. Although when using electrolytes consisting ofcertain salts such as potassium or zinc chlorid it is possible underthese conditions to obtain a fair output, it is Well known that theseelectrolytes are not of a very satisfactory character when used in drycells and in the case of an electrolyte the active component of which islargely or wholly ammonium chlorid, the resulting action with suchimpregnated carbon structure is not of .a character always to affordsatisfactory commercial results. The precipitation of manganese 'peroxidon the bulky porous mass of carbon to secure any degree of uniformity ofdeposition is a matter of extreme difficulty and the irregulardeposition of the peroxid leads to low efficiency because the carbon insome parts has an insufficient amount of depolarizing material, while inother parts there may be even an excess of this agent. If, however, thegraphite or other form of carbon used as conducting material, isintroduced into a solution of manganese nitrate and evaporated todryness with stirring and heated to a temperature of 170 (3., densemange nese peroxid is deposited in intimate contact with and coating thecarbon particles. After all red fumes of oxids of nitrogen havedisappeared, the residue is boiled with water, collected on filters,thoroughly washed with water, and dried. The quantity of graphite orother form of carbon which is added to the solution of manganese nitrateis preferablysuificient to give the right proportion of manganeseperoxid to pulverized conducting material. The 'latter is usuallypresent in amount in excess of the former. This method of formation anddeposition or precipitation yields the depolarizing material insubstantial electrical contact with the particles of graphite, and

. gelatinous vehicle or paste containing the electrolyte or excitingliquid, ordinarily comprising ammonium chlorid.

From the foregoing it will be seen that my invention comprises a cell ofnovel organization having all its parts so coordinated as to yield amaximum of electrical efiiciency and cell longevity. Y

The invention is especially adapted for use with an electrolyte, theactive component of which is ammonium chlorid as manganese peroxidcoated on discrete particles of carbon as herein set forth apparently ispeculiarly reactive with this exciting agent. The extraction with waterreferred to above seemingly tends to open the pores of the densedepolarizing material so that penetrability of electrolyte conjoinedwith compactness is obtained.

Thus it becomes possible to use a prepared manganese depolarizer of adensity heretofore thought to be unfeasible thereby enabling theproduction of that very compact form of dry cell, known as miniature,which is used very largely for making pocket flashlights and the likeand which necessarily must have high depolarizing efiiciency in order tosecure the continuous satisfactory performance of the cell. A furtherdesirable function of the manganese coating is its agglomerating actionwith respect to graphite: The particles of the latter are of anunctuousnature and bond with difficulty but when more or less coated withmanganese peroxid in the state of intimate contact secured by thepresent invention the mass may be shaped without difficulty and acoherent stable molded mass obtained in which the graphite particles arefirmly held. Furthermore it becomes possible to distribute the manganesematerial with a high degree of uniformity'throughout such shaped mass aseach particle of graphite may carry its quota of manganese peroxid,manganites, higher oxid of manganese, or other similar agent employedand no trouble arises from irregular distribution thereof and consequentlack of efiiciency. Again by precipitation in the manner herein setforth, or by equivalent procedure, the manganese mate rial is in trueelectrical contact with the graphite or other carbon particles asdistinguished fromthe mere mixtures of these two substances; for in thelatter case only haphazard contact is secured and such mechanicalmixtures are often lacking in uniformity as the difference in gravity inhandling when preparing the depolarizing mass not infreqnently leads toan undesirable segregation of the components. In its preferred form thematerial employed in the present invention is substantially not affectedin this manner and hence the derived cell is free from the statedobjectionable features characteristic of the cruder types heretoforesuggested.

In my co-pending application Serial No. 765,800 I have disclosed asource of compact or dense and reactive manganese peroxid material andthe present application relates to the use .of such material orequivalent body in intimate association with graphite or otherfinely-diveded carbonaceous conducting material, such for example as maybe obtained by a coating of the character herein described.

What I claim is 1. In the process of making a galvanic cell of theLecianch type the step which comprises depositing from a manganesenitrate solution containing discrete particles of graphite, a dense formof manganese peroxid material on and about said graphite, collecting thegraphite and intimately-associated manganese peroxid and freeing fromwater-soluble matter.

2. In the process of making a miniature dry cell the step whichcomprises depositing from a manganese nitrate solution containingfinelydivided graphite, a dense form of manganese peroxid material as acoating on said graphite, collecting the graphite andintim'ately-associated manganese peroxid, and freeing from water solublematter.

3. In the process of making a galvanic dry cell the step which comprisesdepositing a. dense form of manganese peroxid as a coating on fi-nelydivided graphite, collecting the graphite and intimately-associatedmanganese peroxid and freeing from watersoluble matter.

4.. In the process of making a galvanic dry cell the step whichcomprises depositing a higher oxid of manganese depolarizer as shapedmass; whereby the said coating acts a coating on finely-dividedcarbonaceous as a bonding agent to agglomerate the carconductingmaterial and collecting the rebonaceous material. suiting coatedmaterial. Signed at New York city, in the county of 5 5. In the processof making a galvanic New York and State of New York, this 22nd 5 drycell the step which comprises depositing day of December, A. D. 1914.

a higher oxid of manganese depolarizer as MORDUCH L. KAPLAN. a coatingon finely-divided carbonaceous Witnesses: conducting material collectingand com- ARTHUR MARION,

10 pressing the resulting coated material to a CHAS. C. GILL.

